November 4, 1954

Dr. Ted Puck

Dept. Biophysics
University of Colorado
Denver 7, Colo.

Dear Ted:

I have not hai a wide experience of manipulators, and none at all with their
application to mammalian cells. We have been using a deFonbrune model (sold by
Aloe and Co., St. Lavis), and I would say I am fairly satiafied with it, though
it tends to leak now and then. If you were going to have several different
peopls work on the machine, and it ware to be used routinely, I should think
the extra cost of a direct motion translating type like the deF would be justified.
Otherwise, 1 imagine one of the simpler screw~driven types would suffice (Emerson,
Chaubers). In any event, I hope you try ofl chamber techniqe, and gst a miero-
scopes suitable for it (long focus condenser, phase gontrast). Unless you will
need to wane elaborate miorurgical instruments for operations on cella, the micro-
forge ia not especially useful. Capillaries and needles are best made by hand,
or occaslonaily with the assistence of a hot wire and a dissecting microscédpe.

Ig you'd like t ses 4 machine in operation for cell pedigrees, why don't you
visit ua sometime. I aa spending most of my time now hsolating conjugal pairs
of mating E.coli. :

Yours sinceraly,

Joshus Lederberg